Depends on how loud you want it. If it is for background music, it likely will be adequate.

I think so. I have an older Bose Wave with CD, and it cranks pretty good. The best thing about it is that there is virtually no distortion, even when the volume is very high. I believe that Bose lets you try it risk-free for a period of time. They used to, anyway.

My experience with rooms with high ceilings is that it doesn't take much to be too loud, voices included.
So most any player would be sufficient, although the acoustics wouldn't be that good, unless lots of soft floor coverings/furniture/wall hangings.